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Industrial Statistics with Minitab by Xavier Tort-Martorell Llabres, Lluis Marco Almagro, Pere Grima Cintas

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30.7 Photocopies

The following 35 data of file PHOTOCOPIES.MTW correspond to the duration (measured in number of copies) of toner cartridges of 35 photocopiers of the same type used in 35 offices:
Unnumbered Table
The objective is to find out the probability that a toner cartridge continues operating after 17500 copies.
That is, we want to know its reliability after 17500 copies.

As a first analysis, we can try to answer the question by means of a nonparametric data analysis, without assuming any theoretical model.

Stat > Reliability/Survival > Distribution Analysis (Right Censoring) > Nonparametric Distribution Analysis

We can determine the reliability after 17 500 copies looking at the row in bold face in the previous table. At 13 471 copies the reliability is 0.3714. No other toner fails until 17 500 copies and therefore, the empirical reliability at 17 500 copies is 0.3714.

We will now check which theoretical models best fit our data:

Stat > Reliability/Survival > Distribution Analysis (Right Censoring) > Distribution ID Plot

In this case, our data approximately form a straight ...

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